Mediterranean origin and Miocene–Holocene Old World diversification of meadow fescues and ryegrasses (Festuca subgenus Schedonorus and Lolium)

Authors

  • Luis A. Inda,

    1. Departamento de Ciencias Agrarias y del Medio Natural (Botánica), Escuela Politécnica Superior-Huesca, Universidad de Zaragoza, Huesca, Spain
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    • These two authors contributed equally to this study and should be considered as co-first authors.
  • Isabel Sanmartín,

    Corresponding author
    1. Real Jardín Botánico (RJB-CSIC), Madrid, Spain
    • Correspondence: Pilar Catalán, Escuela Politécnica Superior, Universidad de Zaragoza, Ctra Cuarte km 1, 22071 Huesca, Spain; Isabel Sanmartín, Real Jardín Botánico, Plaza de Murillo 2, 28014 Madrid, Spain.

      E-mails: pcatalan@unizar.es; isanmartin@rjb.csic.es

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    • These two authors contributed equally to this study and should be considered as co-first authors.
  • Sven Buerki,

    1. Jodrell Laboratory, Royal Botanic Gardens, Surrey, UK
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  • Pilar Catalán

    Corresponding author
    1. Departamento de Ciencias Agrarias y del Medio Natural (Botánica), Escuela Politécnica Superior-Huesca, Universidad de Zaragoza, Huesca, Spain
    • Correspondence: Pilar Catalán, Escuela Politécnica Superior, Universidad de Zaragoza, Ctra Cuarte km 1, 22071 Huesca, Spain; Isabel Sanmartín, Real Jardín Botánico, Plaza de Murillo 2, 28014 Madrid, Spain.

      E-mails: pcatalan@unizar.es; isanmartin@rjb.csic.es

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Abstract

Aim

The biogeography of the grass genera Festuca (subgenus Schedonorus) and Lolium, which form one of the world main forage groups, is here reconstructed for the first time using nuclear and plastid DNA data. We aimed to test previous hypotheses on the origin of the group ancestor and on the Holocene versus pre-Holocene dispersals of the most recent fodder grasses.

Location

The Mediterranean Basin and neighbouring regions: North Africa, Southwest Asia, East and West Africa, and Eurasia.

Methods

Sampling included nearly all representatives from the native Old World distribution of this group. We used maximum parsimony, maximum likelihood and Bayesian inference methods to reconstruct phylogenetic relationships. Divergence times were estimated with a Bayesian relaxed clock and secondary calibrations derived from a fossil-dated phylogeny of grasses. Biogeographical scenarios were reconstructed with Bayesian-averaged dispersal–vicariance analysis (Bayes-DIVA) and dispersal–extinction–cladogenesis (DEC), using a stratified palaeogeographical model spanning the last 12 million years.

Results

Meadow fescue (Festuca pratensis) originated in Eurosiberia, Southwest Asia, 2 million years ago (Ma), whereas ryegrasses (Lolium) first diversified in the eastern Mediterranean region around 4.1 Ma, splitting into two autogamous versus allogamous lineages, with Macaronesian Lolium embedded within the latter. An alternative scenario suggests, however, an early split of the Macaronesian ryegrasses. Our results support the hybrid origin of the tall fescue (Festuca arundinacea).

Main conclusions

The ancestor of the fescues and ryegrasses originated in the western Mediterranean in the mid-Miocene. The sister relationship of the tropical African Festuca simensis to Lolium is a novel finding, suggesting a dispersal of the ancestor of the ryegrasses from Asia to East Africa in the early Pliocene. Our reconstruction rejects the hypothesis of a single Neolithic human-mediated dispersal of Lolium species from eastern to western Mediterranean areas, suggesting instead a pre-agricultural distribution of Lolium ancestors along the Mediterranean Basin since the Pliocene.

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